1. Field of the Invention
The present invention relates principally to a jaundice therapeutic apparatus for a neonatal infant, and to a light-emitting diode (LED) therapeutic apparatus provided with a thermal radiating function on the therapeutic apparatus itself.
2. Description of the Related Art
A plurality of technologies as described later is known as the LED therapeutic apparatus for medical use of this type. For example, as a first known technology, there is a light-source apparatus including a number of LEDs, an LED mounting substrate having spherical depressed portions in which a number of the LEDs are disposed, and a flat-panel shaped printed circuit board to which electrode pins of the LEDs are joined, wherein the printed circuit board includes a heat sink formed of a plurality of conducting layers disposed on the surface thereof in an electrically insulated manner, the electrode pins of the LEDs are joined to the respective conducting layers, and the LEDs, the LED mounting substrate, and the printed circuit board are formed integrally (see JP-A-2003-135485).
In the LED therapeutic apparatus of the first known technology, the light-source apparatus allows a number of the LEDs to be integrally and stably mounted on the LED mounting substrate and the printed circuit board. Since the LEDs are mounted stably, not only is manufacture easy, but also troubles during use do not occur often. In addition, since the heat sink is sufficiently provided, the LEDs, as a matter of course, and also a hand piece are prevented from being heated abnormally. Therefore, the LEDs may have a long life span.
A second known technology is a near-infrared LED therapeutic apparatus including a cooling fan provided on an LED driving unit and configured to restrict a temperature rise of LED elements at the time of input and output, wherein the cooling fan is connected to an irradiation color digital output circuit, and heat of the LED elements restricted from rising in temperature by the cooling fan during light irradiation is emitted toward an area of disease (see Claim 8 of JP-A-2009-207605).
In the near-infrared LED therapeutic apparatus of the second known technology, the cooling fan for restricting the temperature rise of the LEDs used for input and output is mounted on the LED driving unit. The restricted heat is emitted from a slit or a gap portion provided on a body portion, so that a small amount of heat provides an ill patient with a comfortable feeling of warmth and enhances a hyperthermic effect. Therefore, by a composite synergic action among physical energy of near-infrared rays, electric vibrations and the sense of warmth, the ill patient may have an enhanced therapeutic feeling and hence satisfactory therapeutic effect upon pain relief (see paragraphs [0019] and [0021] of JP-A-2009-207605).
In addition, a third known technology is a light irradiating apparatus including, in essence, a plurality of LEDs arranged in an annular shape along a center axis, and lenses arranged in front of the respective LEDs in a thermal radiating portion, wherein the respective lenses are arranged so that the optical axes thereof extend obliquely with respect to the center axes to enable light beams emitted from the respective LEDs to converge toward the center axes or diverge from the center axes, wherein a front lens holding member and a rear lens holding member for sandwiching and holding the lenses from the front and the rear are further provided, wherein a mounting member having a plurality of arms extending radially and a thermal radiating fin to be mounted on bottom surfaces of the respective LEDs are further provided, and wherein the mounting member is fixed to the front lens holding member or the rear lens holding member, whereby the LEDs and the thermal radiating fin are fixed by being sandwiched with pressure between the arms and the rear lens holding member (see Claims 1 and 3 of JP-A-2009-231023).
In the light irradiating apparatus of the third known technology, the thermal radiating fin to be in tight contact with the bottom surfaces of the respective LEDs is provided as a thermal radiating structure, and a fan is mounted at a rear end portion of a housing further behind the thermal radiating fin, so that air passes from an outside air intake hole through the thermal radiating fin and is sucked into the fan and exhausted from a rear end opening, so that the thermal radiation is preferably achieved.
In the LED therapeutic apparatuses of the first known technology, the heat sinks formed of the conducting layers are provided on both surfaces of the printed circuit board, and a plurality of through holes of a number corresponding to the number of the electrode pins of the LEDs are provided, conductive collar members are inserted through the through holes, the collar members through which plus electrode pins of the LEDs are inserted are in continuity with the heat sink conducting layer on the back surface side, the collar members through which minus electrode pins are inserted are in continuity with the heat sink conducting layer on the front surface side, and the plus electrodes and the minus electrodes of the LEDs are soldered with the color members inserted therethrough, so that the heat sink conducting layers serve as power distributing elements to the LEDs. Therefore, this technology is superior in terms of configuration since it does not require a heat radiating fan.
However, a number of the LEDs disposed therein are provided in high density and, in addition, the mounting substrate having spherical depressed portions has a significant thickness and includes a number of depressions formed adjacently even though the LEDs generate heat at light-emitting portions, and the LEDs are mounted by fitting in the depressions. Therefore, accumulation or retention of heat is likely in the vicinities of the depressed portions, and the amount of thermal conduction to the printed circuit board via the thin electrode pins is considered to be small. Therefore, heat on the side of the light-emitting portions of the LEDs still increases beyond an allowable range of the junction temperature, so that there arise problems of a short life span of usage, and an occurrence of breakdown due to heat.
The LED therapeutic apparatus of the second known technology is a therapeutic apparatus on the basis of thermal therapy using near-infrared rays, is provided with a cooling fan for restricting the temperature rise of the LEDs, and is configured to use heat restricted by the cooling fan for therapy. However, this therapeutic apparatus cannot be used for therapies which may be hindered by a noise of the cooling fan, and in addition, has a problem as the therapeutic apparatus depends on the life span of usage or the breakdown of the cooling fan.
In the light-irradiating apparatus of the third known technology, a thermal radiating fin in tight contact with the bottom surfaces of the respective LEDs is provided as a thermal radiating structure, and a fan is mounted at the rear end portion of the housing further behind the thermal radiating fin, so that thermal radiation is preferably achieved. However, this therapeutic apparatus also cannot be used for therapies that are hindered by the noise of the fan, and there is a problem such as breakdown due to the life span of usage of the fan.
The allowable temperature of the junction temperature of the LEDs used for the therapeutic apparatus of this type is 125° C., and if the temperature exceeds 125° C., the life span of usage of the LEDs is reduced. For example, the life span of the LEDs is decreased by half every time the allowable temperature of the junction temperature rises 10° C., the percentage of breakdown is substantially doubled, and the life span becomes as short as 30 hours. Then, for example, if the temperature exceeds 175° C., the therapeutic apparatus may be destroyed depending on the case.
Therefore, in the therapeutic apparatus using the LEDs of the known technologies, those having no cooling fan have insufficient thermal radiating structures or functions and have a problem to be solved which is the reduction of the life span of usage by half; and those having the thermal radiation fan have problems to be solved such as being unusable due to being hindered by the noise of the thermal radiation fan, and breakage of the therapeutic apparatus due to the life span of the fan.